On 26.11.2010, at 4.16, Jim wrote:
A quick search of the archives didn't reveal a fix, so I thought I'd ask the list. I was running Dovecot 2.0.2, and noticed a lot of CPU being used up. I discovered a number of IMAP processes burning a lot of cycles, when no connections should have been active. I traced this to the iPhone leaving the IMAP connection apparently active.
I just upgraded to Dovecot 2.0.7, and I'm still seeing connections left active, but haven't seen the high CPU usage yet, but I've only been running 2.0.7 for about 30 minutes.
I tried adding kill_idle to the IMAP config, but that doesn't seem to have helped. Turning off the iPhone does kill the connection, so I know that the iPhone is really keeping the connection alive, but if I can find a way to keep these connections down, I'd really rather have that ability.
IMAP clients generally leave connections open for a long time. I've had an IMAP connection open for weeks. So I think all works as intended, although I don't know specifically how iPhone should work.
Perhaps in some distant future Dovecot could move all such idling connections to be handled by a single "idle process" to free some memory.